ClO in der arktischen Stratosphäre : Konsequenzen für das Verständnis von Wellen- und Mischungsprozessen im arktischen Polarwirbel aus einer Ballonmessung vom 11. Februar 1997 in Kiruna

Winkler, Ulf

Dissertation / PhD Thesis/Book

ClO in der arktischen Stratosphäre : Konsequenzen für das Verständnis von Wellen- und Mischungsprozessen im arktischen Polarwirbel aus einer Ballonmessung vom 11. Februar 1997 in Kiruna

Winkler, U. (Corresponding author)FZJ*

2004
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Jülich : Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, Berichte des Forschungszentrums Jülich 4108, 179 p. (2004) = Bonn, Univ., Diss., 2003

Please use a persistent id in citations: http://hdl.handle.net/2128/136

Report No.: Juel-4108

Abstract: On 11$^{th}$ February, 1997, the TRIPLE balloon was launched in Kiruna, Northern Sweden. It ascended into the lower stratosphere, reached a maximum altitude of 24.1 km and landed in Northern Finland after a 2.5-hour flight. Thanks to advantageous meteorological conditions the balloon passed through the edge region of the polar vortex. Moreover, the data of the TRIPLE flight show that on that day a wave event occurred. The edge region of the polar vortex is of interest because the phenomenon of the polar vortex is closely related to the springtime ozone loss, also known as the ozone hole. Under certain circumstances, the air inside the vortex is forced to remain under polar night conditions for a period of months. Due to the low temperatures reactive chlorine compounds are formed. After the return of sunlight in springtime especially the ClO radical acts as a catalyst of massive ozone depletion. The stability of the polar vortex and the action of the vortex edge as a transport barrier are decisive factors for the extent of ozone depletion. On the gondola of the TRIPLE balloon several instruments were mounted for the measurement of various molecules, among them the ClO/BrO instrument of Research Centre Jülich, an ozone sounding device from the University of Wyoming and the BONBON cryosampler from Johann Wolfgang von Goethe University, Frankfurt am Main. Consequently it was possible to simultaneously observe the wave event and its consequences for the chemistry in the air masses in question. The measured ClO profile thus acted as an indicator of the lowest temperature experienced by the respective air parcel during the event. As the most probable simultaneous explanation for the observed ClO, temperature and pressure profiles a wave standing perpendicular to the earth’s surface is suggested. Chemistry and transport calculations by means of the Chemical Lagrangian Model of the Stratosphere (CLaMS) support this assumption. A theoretical examination shows that such an event can cause horizontal mixing processes. Indeed, the ozone profile measured on the TRIPLE gondola provides indications of an intrusion of ozone-rich air masses originating from the outer vortex edge area or even from outside the polar vortex. This assumption was verified by the tracer-tracer method utilizing the N2O profile of the BONBON cryosampler. Besides these theoretical examinations and considerations, this work also contains a practical part. The working principle of the ClO/BrO instrument, the Chemical Conversion and Resonance Fluorescence (CCRF) method, is explained. The calibration of the instrument and difficulties in measuring BrO by the CCRF method are discussed. Moreover, studies are presented relating to the development of the HALOX aircraft instrument , a modified version of the balloon instrument which has been operated since the end of 2001 on board the Russian high-altitude research aircraft "Geophysica".

Note: Record converted from VDB: 12.11.2012
Note: Bonn, Univ., Diss., 2003

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